When skin or dermis has been traumatized by cutting or burning, scar tissue is formed. In most cases, a small cut or burn area will result in a correspondingly small amount of scar tissue which is not readily discernable to a casual observer. In other cases, where the traumatized area is large and/or lengthy, scarring and scar tissue are quite apparent to a casual observer. This cannot only be embarrassing for the person who is scarred, but can be a distraction for the casual observer. The problem is compounded when, over time, scar tissue tends to darken, become thick and project outwardly from the skin surface, thus becoming more apparent.
In normal wound-healing or sore-healing processes, the abundant vascular network is regenerated in the wound or the sore during the maturing phase and the collagen fibers collect in large bundles. Changing patterns of the connective tissue matrix during growth, development, and repair during the healing of a wound and sore require a delicate balance between the synthesis and degradation of collagen. Under normal circumstances, the balance between the synthesis and degradation of collagen is maintained. However, sometimes this maturing process fails to occur, so that scar tissue remains beneath the covering epithelium for a relatively long period of time and may even develop and become enlarged. This is the clinical nature of a hypertrophic scar.
Although balanced scar formation and remodeling are essential processes in skin wound healing, disorders of excess scar formation remain a common and therapeutically refractory clinical problem. A hypertrophic scar is an excessive scar which by definition has grown in size beyond that required for normal wound healing. Hypertrophic scars can emerge from many wound types, such as from a burn or a sharp incision. A hypertrophic scar is a raised, red and itching enlargement. The scar may be tender to the touch and to other external pressure and can form on every afflicted part of the body.
Hypertrophic scars often remain for a very long time, sometimes through the entire life of the person so afflicted. A hypertrophic scar may transform to a typical soft and pale scar after a year or so. In addition to itching and being relatively unsightly, if the hypertrophic scar happens to overlay a skeletal joint, movement of the joint is often painful and restricted. In the past, such complications were overcome by covering the scar tissue with clothing, makeup, or avoiding contact with other people. This strategy is often not possible, nor desirable. Scar tissue and the tissue adjacent thereto can often become hypersensitive to contact with clothing, and often, a person will not cover the scar tissue to the detriment of socialization. In some instances, a person might not be able to tolerate the application of makeup over scar tissue, again to the detriment of socialization. In other instances, a person may be required to wear a certain type or style of clothing which does not cover scar tissue locations.
Many medical care givers have recognized the problems associated with scar tissue and now include scar tissue management as part of the overall treatment of patients.
A number of techniques have been proposed for the improvement of scars. These include the application of pressure and treatments such as with corticosteroids, collagen, vitamins, such as vitamins E and A, and extracts from vegetable and animal sources. While some of these treatments have had modest success, all of the treatments can be cumbersome, inconvenient or even painful.
The use of pressure dressings is believed to be the first truly effective scar treatment. Application of pressure apparently increases the activity of collagenase, which is an enzyme capable of degrading and modeling the scar tissue and is employed by the body in the equilibrium of the formation and degradation of collagen during the healing process. However, pressure dressings are bulky rendering them uncomfortable to the user and often inconvenient to keep in place on the affected scar tissue.
The application of a steroid such as cortisone also increases the collagen degradation activity of collagenase while decreasing irritation of the scar. With a large amount of extra scar tissue such as a hypertrophic scar or keloid, depending on the severity, a physician often recommends cortisone injections. In less severe cases, cortisone creams or cortisone tapes do show modest benefit. However, creams are often inconvenient to use as they are messy and can stick to and discolor clothing. The uses of tapes are also disadvantageous as such tapes often hold moisture and fall off the affected area. Further, the cortisone creams are required to be rubbed or massaged onto the scar. For some persons, this can be painful. Cortisone injections can also be very painful to the patient.
Vitamin treatment such as vitamin E is believed to decrease the expression of collagen forming genes during the wound healing process and also may soften scars. Cutting vitamin E gelatin capsules in half and squeezing out the oil has been the most common way to apply vitamin E to wounds. Obviously, a vitamin E oil is messy and cutting the capsules in half is a tedious process. The addition of vitamins A and B in creams and lotions is also known, but such creams and lotions are often oily to the touch and do not dry so as to remain in an oily condition or take a long period of time to rub completely into the skin. Again, rubbing or massaging a cream or oil into and/or onto certain scar tissue can be painful to some persons.
It has been discovered in recent years that the shrinkage of hypertrophic scars can be increased by applying silicone-gel plates or sheets to the scars. The exact mechanism by which the silicone-gel interacts with such scars has not been established, however. A number of products are available commercially for this purpose, for instance such products as Dow Corning Silastic Sheeting, Cica-Care (Smith & Nephew), Epi-Derm (Biodermis), Nagosil (Nagor), among others. These products have the form of molded silicone-gel sheets having a thickness of 2-4 millimeters. In treating hypertrophic scars, these sheets are placed over the scars and are worn for a relatively long period of time, often from 3-12 months, until the scars either have decreased or have regenerated. Examples of recent patents which disclose such silicone-gel sheets include U.S. Pat. Nos. 5,759,560; 5,891,076; 5,895,656; and 5,919,476.
The known silicone sheets are relatively rigid and after having been placed over the scar have insufficient adhesion to remain securely in position without some form of assistance. Consequently, it is necessary to secure the sheets against the skin with the aid of securing, stocking, bandage, self-adhesive tape or some like means. The sheets can often trap too much moisture causing irritation on the affected area. Additionally, gel sheets of the type that utilize silicone are tacky to the touch, both on the inner body, body contacting surface and the exterior surface. Having a body contacting surface which is tacky to the touch is advantageous and desirable. However, having an exterior which is tacky to the touch is not. A disadvantage of having a tacky exterior is that articles of clothing tend to adhere to the gel sheet. This presents several problems. One problem is that often the gel sheet adheres to an article of clothing with greater force than it adheres to the skin. Thus, when the article of clothing is removed, the gel sheet is removed from the body. Another problem is that the articles of clothing would adhere to the gel sheet and prevent normal range of motion. An additional problem encountered with gel sheets which are tacky to the touch is that they tend to become soiled more quickly.
Similar silicone materials in the form of topical gels, cremes, and ointments are also available on the market for treatment of wounds, e.g. Kelocote®. Again, these materials remain greasy or oily on the skin and have the disadvantages as described above with respect to comfort and soiled clothing.
Other physical treatments are available, including surgery, X-ray therapy and cryotherapy. Such treatments are expensive or potentially dangerous and not normally recommended.
Accordingly, while there have been physical treatments, compositions and/or articles which contain medicaments which have had modest success in reducing, softening and lightening hypertrophic scars, these prior attempts are expensive, inconvenient to use, difficult to apply or simply have not been very effective in achieving the desired purpose.